Effects of Carryover of Subtherapeutic Antibiotic Dosages on the Bacterial Susceptibility in the Intestinal Flora of Poultry
Due to the frequent use of antibacterials the risk of development of bacterial resistance increases worldwide.The aim of this study was to determine the influence of the carryover of fluoroquinolones on the development of bacterial resistance of E.coli in the intestinal flora of poultry.Different schedules of contamination of the environment of poultry with enrofloxacin were simulated to ascertain changes in the sensitivity of E.coli.Additionally,the environmental distribution of enrofloxacin and its metabolite ciprofloxacin was determined.Minimal inhibitory concentrations(MICs)of E.coli were determined in four different treatment groups of enrofloxacin applied via drinking water (n=10 chicken): A)untreated control.B)recommended dosage(l0 mg/kg,5 days),C)0.3 mg/kg(21 days,subtherapeutic dosage)followed by the recommended dosage and D)1 mg/kg(21 days,subtherapeutic dosage)followed by the recommended dosage.Furthermore,animals were treated with the recommended dosage via drinking water as well as subtherapeutic dosages via food to detect environmental pollutions.Sedimented dust and air filters were analyzed for the two compounds.Chicken treated with the recommended dosage over 5 days developed a slight MIC-shift,which is arranged over the epidemiological cut-off(0.125 yg/ruL)but under the clinical breakpoint(>2 μg/mL).The MICs of the animals treated with 0.3 mg/kg followed by the recommended dosage conducted similarly.Animals treated with 1 mg/kg developed a MIC-shift (bacterial resistance)within 21 days.Under the recommended dosage of 10 mg/kg resistant bacteria were preselected.Both compounds could be detected in dust in concentrations correlating with the applied dosage.In conclusion,during animal treatment antibiotic contaminations occur in the direct environment.Animals exposed to antibacterials in subtherapeutic concentrations pose a risk for the development of bacterial resistances in dependence of dosage.
Scherz,G Stahl,J Glünder,G Schulz,J Hartung,J Kietzmann,M
Department of Pharmacology,Toxicology and Pharmacy,University of Veterinary Medicine Hannover,Founda Clinic for Poultry,University of Veterinary Medicine Hannover,Foundation,Germany Department of Animal Hygiene,Animal Welfare and Farm Animal Behaviour,University of Veterinary Medic
国际会议
XVIth International Congress on Animal Hygiene(第十六届动物卫生国际会议(ISAH 2013))
南京
英文
640-641
2013-05-05（万方平台首次上网日期，不代表论文的发表时间）